How to generate a coordinate field, compute values for each coordinate and plot the results?

Hello,

first, i would like to generate a 2D coordinate field from e.g. 0/0 to 0/100, 100/100 and 100/0 with 10 steps, giving 11x11 = 121 coordinates.

My first try is:

for i = 0:10
A(:,1+2*i) = 0:10:100;
A(:,2+2*i) = (i)*10;
end

I don't like this solution, especially if I want to calculate larger fields.....

second, i would like to calculate a value for each coordinate, e.g. value = f(x,y). How can i plot the calculated values with its x,y coordinates in a 3D plot?

I would be very grateful for assistance and possible solutions!

Christopher

Answer 1

[KSSV]

Read about linspace and meshgrid

x = linspace(0,100,11)  ;
y = linspace(0,100,11)  ;
[X,Y] = meshgrid(x,y) ;
Z = X+Y ;
surf(X,Y,Z)

[Christopher Brokmann]

Thank you.

How do i send all 121 possible coordinate pairs to a function?

e.g. z = f(x,y), is there a solution without loop?

[KSSV]

It can be done......what is the function?

x = 1:100 ;
y = 1:100 ;
[X,Y] = meshgrid(x,y) ;

F = @(X,Y) X.^2+5*Y.^2 ;
Z = F(X,Y) ;
surf(X,Y,Z)

[Christopher Brokmann]

self-written function... i just need a simple example, want to code it by myself

what about the following function as simple example:

function [z]= fxy(x,y)
z = x+y
end

Thank you.

[KSSV]

Thats striaght forward.....I have given examples above......as you are using matrices ..read about element by element operations in matrices. https://in.mathworks.com/help/fixedpoint/ref/times.html

[Christopher Brokmann]

i still have problems to include my function... the only solution i found is with 2 loops, which has the disadvantage of a long run time epsecially for a high number of points for x and y.

x = linspace(0,1,11)  ;
y = linspace(0,1,11)  ;
[X,Y] = meshgrid(x,y) ;

for kk = 1:11
    for nn = 1:11

    Coordinate = [X(kk,nn) Y(kk,nn)];
    
    Z(kk,nn) = f_DeltaWegPunkt(Coordinate,someConstant,...);
    
    end
end